Hand and wrist
Cut Tendons and Nerves in the Hand: Why Urgent, How Repaired
In short
Even a small-looking cut to the palm, fingers or back of the hand can divide the tendons that bend or straighten the fingers and the nerves that give feeling to the fingertips. A cut tendon cannot heal on its own because tension pulls its ends apart, so a cut with these signs should be assessed the same day, and repair is recommended early, usually within seven to ten days. Following the splint and hand therapy programme after surgery matters as much as the operation itself.
What are hand tendon and nerve injuries?
Flexor tendons, which bend the fingers, run from forearm muscles through the wrist and palm into the fingers. Extensor tendons, which straighten them, run along the back of the hand. The finger nerves lie alongside the flexor tendons, so a cut on the palm side can injure both a tendon and a nerve [1][3][4].
Tendons are held under tension like a rubber band. When cut, the ends pull apart and the gap between them prevents natural healing. This is why a completely divided tendon or nerve usually needs surgical repair [1][2][4].
What are the symptoms?
The main signs that may be noticed straight after a cut are [1][2][3][4]:
- Inability to bend one or more joints of a finger, or pain when trying
- Inability to fully straighten a finger, or a drooping fingertip
- Numbness or reduced feeling at the fingertip or along one side of the finger
- Weak grip or clumsiness
- A pale or cold finger, which suggests a blood vessel injury
How do they happen, and what are the risk factors?
Flexor tendon injuries usually result from a cut on the palm side of the fingers, hand, wrist or forearm. A tendon can also tear when a finger is suddenly and forcefully pulled back while gripping something, for example when grabbing an opponent's shirt in football, wrestling or rugby [1].
Even if the surface wound is small, when the full thickness of the skin is cut the structures underneath may be damaged. Because the nerves and blood vessels to the fingers lie very close to the tendons, the same cut can injure them too, and if the vessels are cut the blood supply to the finger may be at risk [1][5].
How is it assessed, and why is it urgent?
The doctor checks whether each finger bends and straightens on its own, and tests grip, fingertip feeling and circulation. X-rays are taken if a bone injury or foreign body is suspected [1].
Urgent assessment matters because, as time passes, the cut tendon ends retract further and repair becomes harder. For flexor tendons, repair is generally recommended within about seven to ten days of injury [1][2]. Deep wounds and wounds with skin loss usually need surgery [5].
First aid and non-surgical treatment
Wash any hand wound under tap water as soon as possible to remove dirt and lower the risk of infection. Cover it with a clean dressing, keep the hand raised and get medical help without delay [5].
Non-surgical treatment is possible only in selected cases. Some small or partial extensor tendon injuries on the back of the hand can heal with a splint alone, but most completely cut tendons need repair [3].
Surgical repair
The operation is done under general or regional anaesthesia, and sometimes under local anaesthesia for extensor tendons. The wound is extended slightly to find the tendon ends, which are then stitched together using special suture techniques [1][2][3].
A completely divided nerve is also repaired surgically, joining the nerve ends with fine stitches. If the gap is large, a piece of nerve taken from elsewhere in the body (a nerve graft) may be used, which can leave a small area of reduced feeling where it was taken [4].
A systematic review of finger nerve repair found that repair gave better sensory discrimination than no repair, but a full return to normal feeling was uncommon. The quality of evidence in this area is limited [7].
Recovery and hand therapy
After surgery, a splint holds the wrist and fingers slightly bent to protect the repair. Hand therapy usually starts within a few days. For flexor tendons the splint is generally worn for five to eight weeks, and for extensor tendons for three to six weeks [1][2][3].
Hand therapy is as important as the operation. A systematic review found that early active motion programmes preserved finger movement better, while passive programmes had a slightly lower rupture risk; modern suture techniques allow early active motion with low rupture rates [3][6].
A tendon takes about three months to reach full strength, and movement can keep improving for up to six months. Nerves regrow at about one millimetre a day; the final result may take two years or more to be seen, and recovery is slower in older people [1][2][4]. Sensitivity to cold may last for two winters [5].
Possible problems include rupture of the repair, tendon adhesions that limit movement, joint stiffness and a painful nerve-end knot (neuroma). Adhesions can be freed with a second operation (tenolysis) [1][2][4].
When should you see a doctor urgently?
Seek same-day emergency assessment if [1][2][5]:
- After a cut to the hand or finger, the finger cannot bend or straighten
- After a cut, the fingertip or one side of the finger feels numb
- The finger is pale or cold, or bleeding does not stop
- The wound is deep, dirty or has skin loss
- After repair, you suddenly lose finger movement or feel something snap
Frequently asked questions
+My finger won't bend after a cut. What should I do?
A finger that cannot bend after a cut suggests a divided flexor tendon. Wash the wound under tap water, cover it, keep the hand raised and get it assessed the same day by a hand surgeon or emergency department [1][2][5].
+Can a cut tendon heal on its own?
No. Tension pulls the cut ends apart, so they cannot heal together naturally. Completely divided tendons usually need surgical repair [1][2].
+Will numbness go away after a finger cut?
Numbness can mean a finger nerve has been cut and should be assessed. Repaired nerves regrow at about a millimetre a day; feeling returns over months but often does not become completely normal [4][7].
Sources
- [1]Flexor Tendon Injuries — American Academy of Orthopaedic Surgeons (OrthoInfo).
- [2]Flexor Tendon Injury — British Society for Surgery of the Hand (BSSH).
- [3]Extensor Tendon Injury — British Society for Surgery of the Hand (BSSH).
- [4]Nerve Injury — British Society for Surgery of the Hand (BSSH).
- [5]Hand Wounds — British Society for Surgery of the Hand (BSSH).
- [6]Flexor tendon repair rehabilitation protocols: a systematic review — The Journal of Hand Surgery (Starr HM, et al.), 2013.
- [7]Outcome of surgical repair of adult digital nerve injury: a systematic review — BMJ Open (Dunlop RLE, et al.), 2019.
This article is general information and does not replace an examination or personal medical advice. In an emergency, go to the nearest emergency department.